Adjustable scalable rack power system and method

ABSTRACT

Systems and method for installing computer equipment and power distribution equipment in facilities is provided. In one aspect, the present invention provides a power distribution rack, and uninterruptible power supply rack and a plurality of equipment racks. A plurality of power cables are run from the power distribution rack to each of the plurality of equipment racks using power cable tracks located on the roofs of the equipment racks.

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.12/719,402, filed Mar. 8, 2010, which is a Continuation of U.S. patentapplication Ser. No. 12/044,161, filed Mar. 7, 2008 (now U.S. Pat. No.7,675,740), which is a Continuation of U.S. patent application Ser. No.11/272,501, filed Nov. 10, 2005 (now U.S. Pat. No. 7,358,439), which isa Continuation of U.S. patent application Ser. No. 10/038,106, filedJan. 2, 2002 (now U.S. Pat. No. 6,967,283), which claims priority toU.S. Provisional Application No. 60/277,428, filed Mar. 20, 2001(Expired) each of which is hereby incorporated herein by reference forall purposes.

FIELD OF THE INVENTION

The present invention relates generally to a system and method forproviding power distribution and mounting facilities for electronicequipment, and more specifically to methods and apparatus for installingand powering computers and related equipment in data centers and otherfacilities.

BACKGROUND OF THE INVENTION

Centralized data centers for computer, communications and otherelectronic equipment have been in use for a number of years, and morerecently, with the increasing use of the Internet, large scale datacenters that provide hosting services for Internet Service Providers(ISPs), Application Service Providers (ASPs) and Internet contentproviders are become increasingly popular. Typical centralized datacenters contain numerous racks of equipment that require power, coolingand connections to communications facilities. It is common in datacenters to use raised flooring, beneath which power cables andcommunication cables may be run between racks of equipment and tofacility distribution panels. In addition, it is common to use the spacebeneath the raised flooring as an air plenum to provide cooling to theracks of equipment. In some facilities, in place of, or in addition tothe use of raised flooring, overhead cable ladders are used to routecables throughout the facility. These cable ladders are typicallyfastened to support members in the ceiling of the facility.

It is often desirable to operate equipment within data centers sevendays a week, 24 hours per day, with little or no disruption in service.To prevent any disruption in service, it is common practice in datacenters to use uninterruptible power supplies (UPSs) to ensure that theequipment within the data centers receives continuous power throughoutany black out or brown out periods. Typically, data centers are equippedwith a relatively large UPS at the main power distribution panel for thefacility. Often, the UPS is a 480 volt 3 phase unit that is selected tohave sufficient capacity to meet the power requirements for all of theequipment within the facility.

Equipment within data facilities typically have 120 volt or 208 voltinput power requirements, and a power distribution unit having a stepdown transformer is often used between the output of the UPS and powerfeeds for equipment racks to lower the 480 volt input voltage to 120volts or 208 volts for the equipment racks. A circuit breaker panel istypically either installed in the PDU or mounted near the PDU.

There are several drawbacks with the traditional design of data centers.First, raised flooring is expensive and cannot be easily accommodated insome facilities, such as those that do not have high ceilings. Second,the routing of cables under raised floors often creates “rats' nests”and it often becomes difficult, if not impossible, to locate particularcables beneath a raised floor. Further, when it is desired to add newequipment to a data center having a raised floor, it is often difficultto pull cables past existing cables under the floor, and the build up ofcables beneath a floor often prevents cooling air from flowing beneaththe floor to electronic equipment racks. In addition, in many locations,building codes require that expensive metal clad cabling be used forpower cables that are located beneath raised floors.

The use of cable ladders that run along the ceiling of a data centerovercomes many of the drawbacks of raised floors discussed above,however, the use of cable ladders also has several drawbacks. Cableladders are somewhat difficult to install, and like raised floors,cannot be readily accommodated in facilities that do not have highceilings. Typically, when cable ladders are used, the location of theladders is determined during the initial design of the data center. Ifit later becomes necessary to add new equipment to the data center or tomove equipment, the location of the ladders may not be in closeproximity to equipment racks, requiring long runs of cables to racks.Further, cable ladders and runs of cables from the ladders to equipmentracks are typically fully in view and often cause a data center toappear to be overcrowded and/or cluttered.

Another drawback in the design of traditional data centers involves thedifficulty in selecting the size of a UPS for the facility. As brieflydiscussed above, many newer data centers are used as web hostingfacilities that essentially lease space and utilities to Internetcontent providers or Internet Service Providers. Often when these datacenters are initially designed, the final power requirements for thefacility are not known, and it is often not for some time, if ever, thata facility becomes fully occupied. If the UPS is selected for fullcapacity, and the facility is operated at substantially below fullcapacity for some time, then the overhead costs of the facility maybecome undesirably high due to the cost of the UPS. Further, there arepower losses associated with a UPS. If a UPS is operated atsubstantially below full capacity, then these losses may becomesignificant when compared with the total power consumption of thefacility. If a UPS for a facility is selected for less than fullcapacity, then it may have to be replaced, at considerable cost, whenthe usage of the facility increases.

In some facilities, UPSs are distributed throughout the facilityallowing smaller UPSs to be used, and providing greater flexibility. Oneproblem with this approach is that installation of the UPS along withthe wiring to racks often requires an electrician. In addition, a powerdistribution unit is often needed between each of the distributed UPSsand the loads that they power. These power distribution units are oftenbulky items that do not fit well within data centers, and/or may requireplacement near a wall on which a circuit breaker panel can be mounted.

SUMMARY OF THE INVENTION

A first aspect of the present invention is directed to an adaptablepower and mounting system for equipment. The system includes a pluralityof equipment racks, each one of the equipment racks has at least a firstpower input to receive power to power equipment contained in each of theequipment racks. The system further includes a first power distributionrack that provides power to the equipment racks, the first powerdistribution rack including a power distribution panel and a pluralityof output power cables, each having a first end coupled to the powerdistribution panel and a second end having a mating connector that mateswith the first power input of at least one of the plurality of equipmentracks.

The plurality of equipment racks and the first power distribution rackcan be designed to be installed in a facility in a predeterminedarrangement, whereby each rack is at a predetermined distance from thepower distribution rack, wherein each of the plurality of cables mateswith a respective one of the plurality of equipment racks, and each oneof the plurality of cables has a length based on the predetermineddistance between the power distribution rack and the respective one ofthe plurality of equipment racks for the one of the plurality of cables.The first power distribution rack can further include a main power inputto receive input power having a first voltage value from a first powersource, and a transformer coupled to the main power input and to each ofthe plurality of output power cables to provide output power having asecond voltage, lower than the first voltage, to the plurality of outputpower cables.

Each of the plurality of equipment racks can have a second power input,and the system can further include a second power distribution rack thatprovides power to the plurality of equipment racks, the second powerdistribution rack including a power distribution panel and a pluralityof output power cables, each having a first end coupled to the powerdistribution panel of the second power distribution rack and a secondend having a mating connector that mates with the second power input ofone of the plurality of equipment racks. The second power distributionrack can further include a main power input to receive input powerhaving a first voltage value from a second power source, and atransformer coupled to the main power input and to each of the outputpower cables of the second power distribution rack to provide outputpower having a second voltage, lower than the first voltage, to theplurality of output power cables of the second power distribution rack.The plurality of equipment racks can be arranged in a type of row havinga first end and a second end, with the first power distribution rackbeing adjacent the first end of the row and the second powerdistribution rack being adjacent the second end of the row.

Each of the plurality of equipment racks can include at least onereceptacle unit having a plurality of power outlets to provide power toequipment in the racks. At least one of the receptacle units in one ofthe equipment racks can have a power cord having a connector thatfunctions as the power input for the one of the plurality of equipmentracks. At least one of the receptacle units in one of the plurality ofequipment racks can be removably mounted to the one of the equipmentracks using a snap fit. The power provided to at least one of theplurality of equipment racks from the first power distribution rack canbe three phase power, and the outlets of a receptacle unit in the one ofthe plurality of equipment racks can be arranged in at least threegroups with at least one outlet in each group being constructed toprovide single phase power from one of the three phases of the inputpower. The receptacle unit in at least one of the plurality of equipmentracks can have an over current device that interrupts power to at leastone outlet upon detection of an over current condition. Each one of theplurality of power cables can include a label that indicates therespective equipment rack for the one of the power cables.

The system can further include a first communications network, and aplurality of the receptacle units and the power distribution rack caninclude a communications circuit coupled to the first communicationsnetwork. The system can further include a consolidator unit having afirst communications circuit coupled to the first communication networkto communicate with the plurality of receptacle units and the powerdistribution rack to receive status information. The consolidator unitcan further include a second communications circuit to communicate witha second communications network. The first communications network can bea power line carrier based network, and the second communicationsnetwork can be an Internet protocol based network.

Each one of the plurality of equipment racks can have a roof sectionwith a power cable track mounted on the roof section, wherein the powercable track is constructed and arranged to contain a portion of at leastone of the plurality of power cables to route the one of the powercables from the power distribution rack to one of the plurality ofequipment racks. The roof section can have an opening to allow a powercable to pass from the power cable track to within the rack or fromwithin the rack to the roof of the rack. The power cable track of afirst one of the plurality of equipment racks can be constructed andarranged to mate with the power cable track of an adjacent second one ofthe plurality of equipment racks to form a continuous power cable trackacross the roof sections of the first one of the plurality of equipmentracks and the second one of the plurality of equipment racks. Each ofthe plurality of equipment racks can include a data cable track mountedon the roof section, and each of the data cable tracks and the powercable tracks can have a length that is greater than a width, and eachone of the data cable tracks can be mounted on the roof of an equipmentrack such that the length of the one of the data cable tracks issubstantially parallel to the length of a power cable track mounted onthe roof of the equipment rack. Each one of the power cable tracks canbe mounted on risers on the roof to provide a space between the one ofthe power cable tracks and the roof to allow a data cable to pass from adata cable track on the roof beneath the one of the power cable tracksand through the opening in the roof. The system can further include abridge power cable track configured to mate with a power cable track ona first one of the plurality of equipment racks and to mate with a powercable track on a second one of the plurality of equipment racks toprovide a continuous power cable track from the first one of theplurality of equipment racks to the second one of the plurality ofequipment racks, wherein the first one of the plurality of equipmentracks and the second one of the equipment racks are separated by anaisle with the bridge power cable track passing over the aisle.

The system can further include an uninterruptible power supply (UPS)having a plurality of power modules and battery modules, the UPS beingpositioned adjacent the first power distribution rack and having aninput coupled to the first power distribution rack to receive inputpower from the first power distribution rack and having an output toprovide one of the input power and backup power derived from the batterymodules to the first power distribution rack.

Another aspect of the present invention is directed to an adaptablepower and mounting system for equipment. The system includes a pluralityof equipment racks, each one of the equipment racks having at least afirst power input to receive power to power equipment contained in eachof the equipment racks, a first power distribution rack that providespower to the equipment racks, the first power distribution rackincluding a power distribution panel and a first plurality of outputpower cables, each having a first end coupled to the power distributionpanel and a second end that mates with the first power input of at leastone of the plurality of equipment racks, and an uninterruptible powersupply (UPS) having at least one battery, the UPS being positionedadjacent the first power distribution rack and having an input coupledto the first power distribution rack to receive input power from thefirst power distribution rack and having an output to provide one of theinput power and backup power derived from the at least one battery tothe first power distribution rack. The first power distribution rackfurther includes a bypass switch having a first input to receive inputpower, a first output to provide the input power to the UPS, a secondinput coupled to the output of the UPS and a second output, wherein thebypass switch has a first electrical position in which the first inputis coupled to the first output and the second input is coupled to thesecond output and a second electrical position in which the first inputis coupled to the second output.

Each of the plurality of equipment racks can have a second power input,and the system can further include a second power distribution rack thatprovides power to the equipment racks, the second power distributionrack including a power distribution panel and a second plurality ofoutput power cables, each having a first end coupled to the powerdistribution panel of the second power distribution rack and a secondend that mates with the second power input of at least one of theplurality of equipment racks.

In yet another aspect of the present invention, an adaptable power andmounting system includes a plurality of equipment racks, each one of theequipment racks having at least a first power input to receive power topower equipment contained in each of the equipment racks, and a firstpower distribution rack that provides power to the equipment racks, thefirst power distribution rack including a power distribution panel and aplurality of output power cables, each having a first end coupled to thepower distribution panel and a second end that mates with the firstpower input of at least one of the plurality of equipment racks. Eachone of the plurality of equipment racks has a roof section with a powercable track mounted on the roof section, wherein the power cable trackis constructed and arranged to contain a portion of at least one of theplurality of power cables to route the one of the power cables from thefirst power distribution rack to one of the equipment racks. The roofsection can have an opening to allow a power cable to pass from thepower cable track to within an equipment rack or from within theequipment rack to the roof of the rack. The power cable track of a firstone of the equipment racks can be constructed and arranged to mate withthe power cable track of an adjacent second one of the equipment racksto form a continuous power cable track across the roof sections of thefirst one of the equipment racks and the second one of the equipmentracks.

Yet another aspect of the present invention is directed to a method ofinstalling equipment in a plurality of equipment racks in a facility.The method includes providing a first power distribution rack having apower distribution panel, determining a location for the first powerdistribution rack and the plurality of equipment racks in the facility,based on the location of the plurality of equipment racks and the firstpower distribution rack, determining a necessary length of each one of afirst plurality of power cables, such that each one of the firstplurality of power cables can be coupled between the first powerdistribution rack and one of the plurality of equipment racks with afirst end of each power cable being coupled to the power distributionpanel and a second end being coupled to one of the plurality ofequipment racks, connecting the first end of each of the first pluralityof power cables to the power distribution panel, and installing aconnector on the second end of each of the first plurality of cables,the connector being selected to mate with an input connector of each ofthe plurality of equipment racks.

The method can further include after installing the connectors,packaging the first plurality of cables and the power distribution rackfor shipment to the facility. Each of the plurality of equipment rackscan include a roof having a power cable track mounted thereon, and themethod can further include routing each of the first plurality of powercables out of a hole in the top of the first power distribution rack,routing each of the plurality of power cables through at least one ofthe power cable tracks, and mating the connector on the second end ofeach of the first plurality of power cables with a connector of a firstpower input cable of one of the plurality of equipment racks. The methodcan further include mounting a first power receptacle unit including thefirst power input cable in at least one of the plurality of equipmentracks, prior to mating the connector on the second end with a connectorof the first power input cable. The method can further include providinga second power distribution rack having a power distribution panel,determining a location in the facility of the second power distributionrack, based on the location of the plurality of equipment racks and thesecond power distribution rack, determining a necessary length of eachone of a second plurality of power cables, such that each one of thesecond plurality of power cables can be coupled between the second powerdistribution rack and one of the plurality of equipment racks with afirst end of each of the second plurality of power cables being coupledto the power distribution panel of the second power distribution rackand a second end being coupled to one of the plurality of equipmentracks, connecting the first end of each of the second plurality of powercables to the power distribution panel of the second power distributionrack, installing a connector on the second end of each of the secondplurality of cables, the connector being selected to mate with an inputconnector of each of the plurality of equipment racks.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is madeto the drawings which are incorporated herein by reference and in which:

FIG. 1 shows a typical layout of a prior art data center;

FIG. 2 shows a layout of a data center in accordance with a firstembodiment of the present invention;

FIG. 3 show a row of equipment racks used in the data center of FIG. 2;

FIG. 4 is a functional block diagram of a power distribution unit anduninterruptible power supply used in the row of equipment racks;

FIG. 5 is a perspective view of the frame of an equipment rack having apower receptacle unit in accordance with one embodiment of the presentinvention;

FIG. 6 is a perspective view of the equipment rack of FIG. 5 showing analternative mounting technique for the power receptacle unit;

FIG. 7 is a top view of equipment racks of the present invention showingthe routing of cables between racks;

FIG. 8 is a perspective view of the equipment rack of FIG. 5 showinganother alternative mounting technique for a power receptacle unit;

FIG. 9A shows a top view of a portion of the power receptacle unit ofFIG. 8 in greater detail;

FIG. 9B shows a mounting portion for a power receptacle unit of the rackof FIG. 8 in greater detail;

FIG. 9C is a side view of the portion of the power receptacle unit ofFIG. 9A; and

FIG. 10 is a diagram showing the interconnectivity of a communicationsbus used in embodiments of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention overcome problems associated withdata centers described above by providing adaptable power distributionand equipment mounting systems for computers and other electronicdevices.

FIG. 1 shows a diagram of the layout of a typical data center 100. Thedata center 100 includes a generator 102, high power switchgear 104, atransformer 106, three UPSs 108A, 108B and 108C, four power distributionunits (PDU) 110A, 110B, 110C and 110D, a battery or bank of batteries112, and twenty-eight rows 114 of racks of equipment. In the data center100, the transformer 106 is used to lower the voltage of power receivedfrom outside the facility or from the generator to a voltage level oftypically 480 volts. The switchgear provides switching of the powerbetween the generator and an outside power source and the UPSs. The UPSsin conjunction with the battery 112 provide uninterruptible power toeach of the PDUs. Each PDU typically contains a transformer, and powerdistribution circuitry, such as circuit breakers, for distributing powerto each of the racks in the data center. Problems associated with datacenters like that shown in FIG. 1 are described above in the

BACKGROUND OF THE INVENTION

FIG. 2 shows a diagram of the layout of a data center 200 in accordancewith a first embodiment of the present invention. Like data center 100,data center 200 includes a generator 202, switchgear 204, and atransformer 206 and forty-two rows 214 of racks of equipment. Datacenter 200 differs from data center 100 in that it does not contain thelarge UPSs 108A, 108B, 108C and 108D, batteries, and the large PDUs110A, 110B, 110C and 110D of the data center 100. Rather, data center100 includes UPS racks 208 having batteries and PDU racks 210 that aredistributed throughout the racks of equipment. In one embodiment of thepresent invention, as shown in FIG. 2, each row of equipment 214includes a UPS rack 208 and a PDU rack 210 located at each end of therow.

In FIG. 2, each row of racks 214 includes fourteen racks. In embodimentsof the present invention, the number of racks and the function ofequipment in the racks can vary. FIG. 3 shows an exemplary row of racks214, used in embodiments of the present invention. The row of racks 214includes a total of 9 racks, including UPS racks 208A and 208B, PDUracks 210A and 210B, and five equipment racks including three serverracks 220A, 220B, and 220C, a storage array rack 222, and a router rack224. In one embodiment of the present invention, the racks may bemodified standard 19 inch racks, such as those available from AmericanPower Conversion Corporation of W. Kingston, RI under the trade nameNETSHELTER®.

The server racks include a plurality of servers 226 along with atransfer switch 228. As understood by those skilled in the art, theservers may be network servers that are commercially available from anumber of sources. The transfer switch 228 is used in some embodimentsof the invention to switch between a main source of power and aredundant source of power in the rack. The use of distributed transferswitches in each rack provides significant benefits over prior artsystems that have one centrally located transfer switch. In particular,the use of distributed transfer switches in individual racks increasesthe power availability to the racks by protecting against faults thatmay occur in the distribution system between the central source of powerin a facility and a rack.

The storage array rack 222 is used to house data storage equipment, suchas that available from EMC Corporation of Hopkinton, Mass. In addition,the storage array rack can be used for servers, routers or otherequipment. In addition, other, non-racked devices, such as tower serverscould be powered by power distribution systems of the present invention.

The router rack 224 houses a DC rectifier 230, routers 232 and switches234. The routers and switches are communication devices that are wellknown to those skilled in the art. The DC rectifier is used to convertAC power to DC power to power DC devices contained in the router rack.

Each of the UPS racks 208A and 208B includes a modular uninterruptiblepower supply (UPS). Each UPS includes a plurality of power modules 236,a plurality of battery modules 238, and an intelligence module 240. Theintelligence module 240 provides control of subsystems contained withinthe UPS. The power modules provide regulated output AC power, provide DCcharging current for the battery modules, and convert DC power from thebattery modules to AC power, upon disruption of facility power. Thebattery modules provide back up power to the power modules upondisruption of facility power.

In one embodiment, the power modules and the battery modules can beindividually added to or removed from the UPS to accommodate differentload requirements, thereby providing an economical and expandabledesign. Further, the use of multiple power modules and battery modulesprovides redundancy in each of the UPSs by allowing continued operationof the UPSs, despite a failure of any one power module or batterymodule. In one embodiment, the UPSs may be implemented using a UPS likethe Symmetra® UPS available from American Power Conversion Corporationand described in U.S. Pat. No. 5,982,652, titled “Method and Apparatusfor Providing Uninterruptible Power,” which is incorporated herein byreference. In embodiments of the present invention, the UPS rack may beconfigured to provide front to back cooling for the components of theUPS.

In the embodiments shown in FIGS. 2 and 3, a UPS rack and one PDU rackis included at each end of the row of racks. As is described furtherbelow, the use of two UPSs and two PDUs provides further redundancy inthat power can continue to be supplied to the racks in the event thatone of the UPSs and/or one of the PDUs completely fails. The use of thetwo UPSs and PDUs provides the capability to operate in data centershaving redundant power sources, and provides redundant power to each ofthe racks. Some servers and other equipment typically contained in racksin data centers have two power inputs for redundancy purposes. Inembodiments of the present invention that provide redundant power, theseequipments having redundant inputs can be accommodated. In addition, theuse of the transfer switch allows equipment that does not have redundantinputs to be powered from redundant sources. The transfer switchreceives power from each of the redundant power systems and providesoutput power from one of the two input systems.

As understood by those skilled in the art, the present invention is notlimited to a system having two UPS s and two PDUs as shown in FIGS. 2and 3, but rather, includes systems having only one UPS and PDU and morethan two UPSs and PDUs.

The PDU racks 210A and 210B provide power transformation, circuitbreaker protection and distribution of input power to each of the racksin the row. Each PDU rack includes two circuit breaker distributionpanels 242A and 242B, a service bypass switch 244, an input circuitbreaker 241 and a transformer 246. The service bypass switch includesswitches 243, 245 and 247. FIG. 4 shows a functional block diagram ofthe PDU 210A (PDU 210B being substantially identical to PDU 210A) alongwith the connections between the PDU and the UPS 208A in one embodimentof the present invention. In the embodiment shown in FIG. 4, thetransformer 246 receives the 480 volt, three phase input power of thePDU rack and provides 208 volt, three phase power to the UPS rack. Inother embodiments of the present invention, depending on characteristicsof the local power, the transformer can be designed for other inputvoltages and output voltages and the entire PDU may be designed forsingle phase power. In FIG. 4, for simplicity, a single connection isshown between each of the devices. As understood by those skilled in theart, individual connections for each phase of the power, neutral, and anoptional chassis ground are actually provided between each of thedevices.

In the embodiment shown in FIG. 4, the UPS rack receives the power fromthe transformer, and if the input power is within predeterminedtolerances, the power is routed back to the PDU rack. If the power isnot within tolerances, or if there is a power outage, the UPS rack willswitch to battery back-up mode and provide power generated by the UPS tothe PDU rack. The distribution panels 242A and 242B contain circuitbreakers and provide for a plurality of outlet points from which 208volt, three phase power can be distributed to the equipment racks. InFIG. 4, the distribution panels have seven outlet circuits. In otherembodiments of the present invention, distribution panels having more orless outlet circuits may be used. Further, in embodiments of the presentinvention, the PDU rack may include fuses and voltage and/or currentmonitors.

The bypass switch 244 is contained in the PDU and provides for manualbypass of the UPS to provide power directly to the distribution panelupon failure of the UPS, to replace the UPS or for any other reason. Theuse of the bypass switch in the PDU provides significant advantages inembodiments of the present invention over the prior art by allowing aUPS to be replaced due to failure or for upgrade purposes. In prior artdata centers that use 480 volt UPSs, the cost of bypass switches, andthe size of the switches that must be used for 480 volt power, oftenmake their use prohibitive.

In the embodiment shown in FIG. 4, the bypass switch actually includesthree switches 243, 245 and 247. As will now be described, the use ofthe three switches provides continuous power when the UPS is switchedout, and reduces transients and arcing that can occur during switching.During normal operation, switches 243 and 247 are in the closed positionand switch 245 is in the open position to route all power through theUPS. When it is desired to bypass the UPS, switch 245 is first closedand then switches 243 and 247 are open. Similarly, when it is desired toadd a UPS back in the system, switches 243 and 247 are closed prior toopening switch 245.

In one embodiment of the present invention, as shown in FIG. 3, inputpower to the PDU rack is received from underneath the rack through, forexample, a raised floor. In other embodiments, the input power to thePDU rack may be received through the roof of the PDU rack, or throughthe back of the rack. Power from the PDU rack to the UPS rack is runeither through the sides of the rack, over the roofs of the racks orthrough the floor beneath the racks.

In one embodiment of the invention, distribution of power from thedistribution panels in the PDU racks to each of the equipment racks isaccomplished using a plurality of flexible power cables of variouslengths. In the embodiment shown in FIG. 3, the flexible cables arerouted through the top of the PDU rack and through overhead tracks tothe equipment racks. In this embodiment, each of the power cables isterminated using a standard power connector, and each of the equipmentracks has an input power cable having a mating connector for thestandard connector on the power cables allowing each of the racks to besimply connected to the PDU without the need of an electrician. In oneembodiment, the input power cable for a rack is a power cord of a powerreceptacle unit mounted in the rack.

FIG. 5 is an isometric view of a rack 250 that in one embodiment is usedfor the server racks 220A, 220B and 220C. In FIG. 5, the rack 250includes a front door 252, but is shown without side panels and a backdoor. The rack includes a front section 254 and a back extension section256. The front section 254 is used to contain nineteen inchrack-mountable servers and other equipment. The back extension section256 is used for power and signal distribution between equipment mountedin the rack. The back extension section includes a first side panel 258,a second side panel 260, and a roof section 266. The roof section has afirst opening 268 and a second opening 270. The first opening 268 andthe second opening are used to pass data and power cables into and outof the racks.

In the rack of FIG. 5, a power receptacle unit 262 is mounted to thefirst side panel 258 using brackets 264A and 264B The power receptacleunit 262 has an opening 272 to receive a power cord (not shown in FIG.5) for the power receptacle unit. Similarly, a second power receptacleunit may be mounted to the second side panel 260. As shown in FIG. 6, inan alternative embodiment, the power receptacle unit 262 is mounted onraised brackets 263A and 263B. Depending on the configuration ofequipment and the back door of the rack, the use of the raised bracketsmay provide greater accessibility to the power outlets of the powerreceptacle unit. As described further below, in other embodiments, apower receptacle unit may be mounted to the rack without use of bracketsand requiring no tools for installation or removal. In addition toshowing the use of raised brackets, the rack 250 of FIG. 6 is also shownwith the front door removed.

In one embodiment of the present invention, as will now be describedwith reference to FIG. 7, one or more of the racks includes an overheadpower track and an overhead data track, both of which are attached tothe roof of the rack. The power track is used for passing power cablesin a side-to-side direction from one rack to another. The data tracksare used for passing data cables in a side-to-side direction from onerack to another. The use of the overhead tracks on the UPS racks isoptional depending on the path used to run power between the PDU racksand the UPS racks and to run data cables between the racks. The tracksare designed such that the track of one rack lines up with the tracks ofadjacent racks when the racks are positioned side-by-side in order tocreate a continuous track for a row of racks of any length.

FIG. 7 is a top view of racks 208A, 210A, 220A, 220B, and 220C (FIG. 3),and FIG. 7 shows the top panels 273, 274, 276, 278 and 280 of each ofthe racks and also shows power tracks 282A,282B, 282C, 282D and 282E anddata tracks 284A, 284B, 284C and 284D that run between the racks. Thetop view of FIG. 7 also shows power bridge tracks 286A and 286B and databridge tracks 288A, 288B and 288C. The bridge tracks are used inembodiments of the invention to connect the tracks of two racks located,for example, in two rows separated by an aisle to allow power and datacables to pass from one rack to a rack in another aisle. Similarly,bridge tracks may be used for data cables. The top panels 282C, 282D and284E of the server racks are longer than top panels 282A and 282B of theUPS and PDU racks. The longer top panels extend over the back extensionsection 258 (FIG. 5) of the server racks.

Each of the power tracks has a slot 298 to allow the input power cablesto pass from the openings in the top of the racks into the power tracks,and each of the data tracks has an opening 300 to allow data cables topass from openings in the top of the racks to the data tracks. Each ofthe power tracks has a tunnel 296 to allow data cables to pass beneaththe power tracks to openings in the top of the racks. In otherembodiments, the data tracks may be raised off of the roof of the racksto allow power cables to pass beneath.

In FIG. 7, five flexible power cables 290A, 290B, 290C and 290D passthrough the top of the PDU. Cable 290A mates with input power cable 292Aof server rack A through mating connector pair 294A, cable 290B mateswith input power cable 292B of server rack B through mating connectorpair 294B, and cable 290C mates with input power cable 294C of serverrack C trough mating connector pair 294C. Power cable 290D passes fromthe PDU through the power tracks and onto power bridge track 286A. Powercable 290E passes from the PDU through the power tracks and onto powerbridge track 286B. Data cables 302 are run in the data tracks and passinto the racks either through holes 304 or holes 306. The data cablesmay also be run to other racks over data bridge tracks 288A, 288B and288C.

In one embodiment, each of the flexible power cables is pre-wired intothe PDU prior to the delivery of the PDU rack to a data center and theflexible power cables are packaged with and shipped with the PDU. Eachof the flexible cables is sized based on the distance from the PDU rackto the equipment rack at which it terminates. In this embodiment, adrawing representing the installation plan for the system, along with acomputer aided design (CAD) program may be used to determine therequired lengths of the flexible power cables. Since the lengths of thecables are determined prior to installation, the ends of the powercables can be terminated with a connector prior to installation, andtherefore, at installation, the power cables may be routed to the rackswithout any cutting of power wiring during the installation process.

As discussed above with reference to FIG. 5, each of the equipment rackscan include two power receptacle units. Each power receptacle unit has aplurality of output receptacles for powering the equipment in thecorresponding rack and has an input power cable having a connector whichmatches the connector of one of the flexible power cables provided bythe power distribution unit. As described above, in one embodiment, thepower to each of the equipment racks is 208 volts three phase power. Inthis embodiment, each of the power cables from the PDUs to the equipmentracks has at least five conductors, one conductor for each of thephases, a neutral conductor and a ground conductor. In one embodiment,each of the power receptacle units contains a plurality of groups ofreceptacles, with each group of receptacles wired to provide either 120volt from one of the three input phases or to provide 208 volt power.Also, in embodiments of the present invention, each outlet in eachreceptacle unit, or groups of outlets, may be separately protectedagainst overload by a circuit breaker, fuse, or similar device containedwithin the receptacle unit.

In embodiments of the present invention, the availability in each rackof single phase power from each of three phases of a three phase systemsignificantly simplifies balancing the load on the three phase system.As is known in the art, it is desirable to draw approximately the samecurrent in each phase of a three phase system. In typical prior artsystems, power from only one phase is available in each equipment rackin a data center. Accordingly, balancing of the three phase power mustoccur at the rack level, which is often very difficult to accomplish,particularly for racks having equipment with variable power draw. Incontrast, in embodiments of the present invention, balancing of thethree phase power can be achieved by switching equipment in a rack fromone group of outlets in a receptacle unit to another group of outlets ina receptacle unit.

The provision of both 208 volt power and 120 volt power in racks of thepresent invention provides additional flexibility over prior art racksthat typically are wired for one of 120 volts and 208 volts. Inaddition, in one embodiment that will now be described with reference toFIG. 8 and FIGS. 9A-9C, the power receptacle units are removably coupledto the racks to allow replacement of a receptacle unit without usingtools.

FIG. 8 shows a power receptacle unit 262 mounted to the second sidepanel of the rack 250. As shown in FIG. 8, both the first and secondside panels include pairs of slots 310 for mounting a power receptacleunit. In FIG. 8, only one of the slots of each pair is visible for thefirst side panel of the rack. The power receptacle unit 262 includes twopairs of tabs 312 that mount into two of the pairs of slots 310 to mountthe receptacle unit to the rack. In FIG. 8, the tabs 312 mate with theuppermost and lowermost pairs of slots, however, in other embodiments,shorter receptacle units can mate with other pairs of tabs.

FIG. 9A shows a top view of a portion of the receptacle unit 262including one of the pairs of tabs 312, and FIG. 9C shows a side view ofthe portion of the receptacle unit 262. FIG. 9B shows a front view of aportion of the second side panel 260 illustrating one of the pairs ofslots 310 in greater detail. As best seen in FIG. 9C, each of the tabs312 has a top portion 314 and a neck 316. When mounting the receptacle262, the top portion 314 is inserted through the larger portion of theslot 310, and the receptacle is then moved so that the neck 316 is inthe narrow portion of the slot 310, so that the top portion of the tabholds the receptacle unit in the slot.

The ability to easily replace receptacle units in racks of the presentinvention provides further flexibility to accommodate a greater varietyof equipment. For example, a receptacle unit having all 120 volt outletsmay be replaced with a receptacle unit having a mixture of 120 volt and208 volt outlets, or all 208 volt outlets if 120 volt equipment isreplaced by 240 volt equipment.

As discussed above, each of the equipment racks may have two powerreceptacle units coupled to two different UPSs through two differentPDUs and two different flexible power cables. As described above withreference to FIGS. 2 and 3, in one embodiment having two UPS s and twoPDU racks for powering a series of equipment racks, the equipment racksare arranged in a row with one UPS and one PDU rack positioned at eachend of the row. By positioning the PDUs at opposite ends of the row, thenumber of cables at any one time in the overhead tracks can be uniform.In other embodiments of the invention, the equipment racks do not needto be contained in one linear row, but rather, could be in multiple rowsor the racks may be arranged in a non-linear fashion. Overhead bridgesbetween the tracks may be used to run the flexible cabling betweennon-adjacent racks.

In one embodiment, each of the UPSs, the PDUs and the power receptacleunits may include a communication circuit for status monitoring by acontroller via a common communication bus. FIG. 10 shows a number ofreceptacles 262, one of the UPSs, and one of the PDUs of a powerdistribution network of the present invention, coupled over acommunication bus 318 to the controller 320 to allow status monitoringof the power distribution system. The communication bus may beimplemented using any one of a number of known network topologies, andin one embodiment, is implemented using a modified version of the CommonApplication Standard (CAL) over IP in addition to SNMP and HTTP. Inanother embodiment, the communication bus may be implemented using apower line carrier network.

In one embodiment, the controller provides consolidated information toan IP based network using SNMP, HTTP or some other known protocol. Thecontroller may also include software to prevent access from the IPnetwork to the communications bus. The controller may be mounted in oneof the equipment racks, in a PDU rack or in a UPS rack.

In one embodiment of the present invention, some or all of thereceptacle units contain current (or power) monitoring devices formonitoring the total current through the receptacle or the currentthrough each of the outlets of the receptacle. In this embodiment, thecurrent measured in the receptacles can be communicated to thecontroller over the communications bus to allow the controller to detectany present or impending over current conditions. In one embodiment,additional current (or power) monitors, coupled to the communicationsbus, can be distributed throughout the power distribution network toprovide values of current (or power) to the controller. In addition,each of the receptacles may have a display that displays the current orpower draw for the receptacle unit to determine if additional devicescan be powered from the unit. Further, as described in copending U.S.patent application Ser. No. 10/038,701, filed on Jan. 2, 2002, titledMETHODS AND APPARATUS FOR PREVENTING OVERLOADS OF POWER DISTRIBUTIONNETWORKS, assigned to the assignee of the present application, andincorporated herein by reference, the controller and power monitoringdevices can be used in conjunction with the controller along withsoftware contained in computers contained in the equipment racks todetermine maximum power levels in the power distribution system.

In FIG. 3, the UPSs are placed at the ends of the rows of racks.Embodiments of the present invention are not limited to systems in whichthe UPS racks are placed at the ends, however, as described above, inembodiments of the present invention, there are advantages to placingthe UPSs at the end of the rows. Specifically, the placement of the UPSsat the end of the rows allows easy access to the UPSs for replacementfor repair or upgrade. Further, in redundant power systems having twoPDUs, as described above, the placement of the PDUs at the ends of therows allows the number of cables at any point in the tracks in a row ofracks to be kept uniform. Nonetheless, in other embodiments of thepresent invention, the UPSs and PDUs may be installed in the center of arow or at any other position in a row of racks.

In embodiments discussed above, racks are described as being arranged inrows. In different embodiments, rows of racks may be linear rows, curvedrows, have spaces (i.e., aisles) between racks, or be arranged in someother configuration.

Having thus described at least one illustrative embodiment of theinvention, various alterations, modifications and improvements willreadily occur to those skilled in the art. Such alterations,modifications and improvements are intended to be within the scope andspirit of the invention. Accordingly, the foregoing description is byway of example only and is not intended as limiting. The invention'slimit is defined only in the following claims and the equivalentsthereto.

1. An adaptable power and mounting system for equipment, the systemcomprising: a plurality of equipment racks, each one of the equipmentracks having at least a first power input to receive power to powerequipment contained in each of the equipment racks; and a first powerdistribution rack that provides power to the equipment racks, the firstpower distribution rack including a power distribution panel and aplurality of output power cables, each having a first end coupled to thepower distribution panel and a second end having a mating connector thatmates with a mating connector of the first power input of at least oneof the plurality of equipment racks. 2.-81. (canceled)